Department of Conservation (DoC) pest control experts are looking at changes to rat bait distribution systems after the death of six native parrots at Pukaha Mount Bruce.
Toxicology tests revealed traces of rat poison in three of the kaka found dead in the Pukaha forest in November.
Staff had earlier noticed some
of the about 100 kaka living in the 942ha forest were tampering with the ground-based plastic distribution stations that deliver bait containing the rat poison diphacinone.
"We knew some of them had been interfering with the bait stations on the hill behind the visitors centre, so we modified those stations, but later on, we found they were interfering on a wider basis," said DoC Wairarapa area manager Chris Lester.
The kaka were eating the cereal pellets containing the poison and Mr Lester said staff immediately began adding metal plates to the 1200 bait stations within the reserve to stop the birds getting into the plastic containers.
"It was a really massive task. It took weeks and weeks to modify the stations along 130km of track," he said.
The kaka were introduced to Pukaha Mount Bruce in 1996, and Mr Lester said they had grown from a handful into about 100.
He said this is the first issue they have had with the kaka, and DOC was "very confident" the modifications had worked, as they have had no more losses.
DoC's threats unit manager Jeff Flavell said DoC has discussed the problem with neighbouring regional councils, and has briefed staff across the country so they are aware of the kaka's potential behaviour.
Mr Flavell said without poison, rats and other predators would effectively wipe out the populations of native birds now growing in protected reserves around New Zealand.
